What is it?

Traditionally we just use a combination of a user name and password to access a secure web site or service. With the current pace of malware, phishing techniques and other methods used in identity theft, a more-secure method is needed.

Multi-factor authentication is known by several terms and acronyms like:

  • mfa
  • 2fa
  • 2-factor

Essentially a multi-factor authentication method includes at least 2 types of credentials:

  • Something you know. Example: a password
  • Something you have. Example: a smart phone

When you are using an online account with multi-factor authentication enabled, you will be prompted to enter the 2nd password after you login with your traditional user name and password.

Since you are already familiar with a traditional password, we will focus on the 2nd authentication factor, the “something you have”.

Types of multi-factor authentication

Multi-factor authentication can be implemented in several ways. These are the most common methods in use and how they work:

Scratch codes

A static list of codes provided by the site that can either be used one-time each or in a specific order. Scratch codes are often used as an emergency fall-back method with other types of multi-factor authentication.

OTP (One-time password)

A one-time use only temporary password. The OTP can be accessed in different ways depending on how it has been implemented. These are the most common types in use.


The OTP codes are sent to your phone in an SMS message when you attempt to login.

TOTP (timed one-time pasword)

The OTP codes are generated using an app on your smart phone like ‘Google Authenticator’:

Smartphone (push)

An app installed on your smartphone will prompt you with a notification to ‘Accept’ the authentication request. This method is only used by sites that have a dedicated authenticator app like the ‘Microsoft Authenticator’.

Hardware Tokens

Hardware tokens are the most secure multi-factor method available. Many large organizations are requiring hardware tokens for employees. Hardware tokens are a recommended investment in your online security. Due to the complexity of this topic, it will get a dedicated post in the future.

Recomended hardware tokens